Onboard monitoring of fatigue damage rates in the hull girder

Most new advanced ships have extensive data collection systems to be used for continuous monitoring of engine and hull performance, for voyage performance evaluation etc. Such systems could be expanded to include also procedures for stress monitoring and for decision support, where the most critical wave-induced ship extreme responses and fatigue damage accumulation can be estimated for hypothetical changes in ship course and speed in the automatically estimated wave environment.The aim of this paper is to outline a calculation procedure for fatigue damage rate prediction in hull girders taking into account whipping stresses. It is conceptually shown how such a method, which integrates onboard estimation of sea states, can be used to deduce decision support with respect to the accumulated fatigue damage in the hull girder.The paper firstly presents a set of measured full-scale wave-induced stress ranges in a container ship, where the associated fatigue damage rates calculated from a combination of the rain-flow counting method and the Palmgren-Miner damage rule are compared with damage predictions obtained from a computationally much faster frequency fatigue analysis using a spectral method. This analysis verifies the applied multi-modal spectral analysis procedure for fatigue estimation for cases where hull girder flexibility plays a role.To obtain an automated prediction method for the fatigue damage rates it is in the second part of the paper shown how a combination of the full-scale onboard acceleration and stress measurements can be used to calculate sea state parameters. These calculated environmental data are verified by a comparison to hindcast data.In the third part of the paper the full-scale fatigue stress ranges are compared to results from an analytical design oriented calculation procedure for flexible ship hulls in short-term estimated sea states.Altogether, it is conceptually shown that by a combination of the onboard estimated sea state parameters with the described analytical fatigue damage prediction procedure a method can be established for real-time onboard decision support which includes estimates of fatigue damage rates.     

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沥青路面设计参数探讨

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轮胎尺寸对汽车结构疲劳累积损伤影响研究

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双层有轨电车是路面轨道交通工具的重要型式之一.自有轨电车引入中国内地以来,近10年得到快速发展.但相比国外,双层有轨电车在中国内地的应用和适应性仍有较大发展和进步空间,有必要针对双层有轨电车开展进一步研究.介绍双层有轨电车国内外应用现状,详细叙述现代双层有轨电车技术平台、关键技术参数,分析适应性及应用前景.针对双层有轨...     

深水悬链复合锚泊线疲劳损伤计算

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AzLM型计轴远程诊断系统

针对现场维护中遇到的泰雷兹AzLM型计轴系统在运行过程中存在故障高发、延时长的问题,开发了远程诊断功能,便于超前预防潜在的隐患以及故障后能快速远程诊断分析,压缩故障延时,提高设备保安能力。     

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